Re: Sorting Problem - Mailing list pgsql-general

Ok, thanks for all the discussion followed, vey educational :-))
But nobody really followed up my question :-(

For example, you have a table that is displayed in the browser. You want to let
the user do sorting on one or multible columns, including those which contain
localized strings.

If the db supports sorting for multi-linguages, you can retreive all the rows
and do "ORDER BY" on the columns directly.

But if db doesn't support that, in Java, you will have to retrieve all the rows
first, sort the objects on multiple columnes listed in the "ORDER BY" in java.
It is much slower than the previous one.

My problem is that if initdb is done with en_US, if a customer in Japan request
the page with that sorted table, the text is not sorted in a Japanese one. Then
I have a problem.

Any suggestions on that ??


Dennis Gearon wrote:
> I agree, mostly. In the case of a database, I would bet that the
> INTERNAL, IN-APPLICATION processing FAAAAAAAAAAARRRRRRRRRRR exceeds that
> of sending and receiving it.
>
>     i.e. comparisons, sorts, triggers, indexes, views, functions,
> logging to tables, ordering by,
>         grouping, etc.
>
>     except backups, restores, logging to text files (these would be good
> in UTF8)
>
> Bruce Momjian wrote:
>
>> I think the question is how often are you passing data around/storing it
>> _in_ your application and how often are you processing it.
>>
>> ---------------------------------------------------------------------------
>>
>>
>> Dennis Gearon wrote:
>>
>>> I agree with all of that except for one caveat:
>>>
>>>     all my reading, and just general off the cuff thinking, says that
>>> processing variable width characters SIGNIFICANTLY slows an
>>> application. It seems better to PROCESS fixed width characters (1,2,4
>>> byte), and TRANSMIT variable width characters (avoiding the null
>>> problem.)
>>>
>>> Gianni Mariani wrote:
>>>
>>>
>>>> Dennis Gearon wrote:
>>>>
>>>>
>>>>> Got a link to that section of the standard, or better yet, to a
>>>>> 'interpreted' version of the standard? :-)
>>>>>
>>>>> Stephan Szabo wrote:
>>>>>
>>>>>
>>>>>> On Wed, 13 Aug 2003, Dennis Gearon wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Dennis Bj?rklund wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>> In the future we need indexes that depend on the locale (and a
>>>>>>>> lot of other changes).
>>>>>>>>
>>>>>>>
>>>>>>> I agree. I've been looking at the web on this subject a lot
>>>>>>> lately. I
>>>>>>> am **NOT** a microslop fan, but SQL-SERVER even lets a user define a
>>>>>>> language(maybe encoding) down to the column level!
>>>>>>>
>>>>>>> I've been reading on GNU-C and on languages, encoding, and
>>>>>>> localization.
>>>>>>>
>>>>>>> http://pauillac.inria.fr/~lang/hotlist/free/licence/fsf96/drepper/paper-1.html
>>>>>>>
>>>>>>> http://h21007.www2.hp.com/dspp/tech/tech_TechSingleTipDetailPage_IDX/1,2366,1222,00.html
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> There are three basic approaches to doing different langauges in
>>>>>>> computerized text:
>>>>>>>
>>>>>>>   A/ various adaptations of the 8 bit character set, I.E. the
>>>>>>> ISO-8859-x series.
>>>>>>>   B/ wide characters
>>>>>>>   ********This should be how Postgress stores data
>>>>>>> internally.********
>>>>>>>   C/ Multibyte characters
>>>>>>>   ********This is how Postgress should default to sending data
>>>>>>> OUT of the application,
>>>>>>>           i.e. to the display or the web, or other system
>>>>>>> applications********
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> SQL has a system for defining character set specifications,
>>>>>> collations and
>>>>>> such (per column/literal in some cases).  We should probably look
>>>>>> at it
>>>>>> before making decisions on how to do things.
>>>>>
>>>>>
>>>>>
>>>> I thought UNIX (SCOTM) systems also had a way of being able to
>>>> define collation order.
>>>>
>>>> see:
>>>>   ftp://dkuug.dk/i18n/WG15-collection/locales
>>>>
>>>> for a collection of all ISO standardized locales (the WG15 ISO work
>>>> group's stuff).
>>>>
>>>> Do a "man localedef" on most Linuxen or UNIXen.
>>>>
>>>> As for wide characters vs multibyte, there is no clear winner.  The
>>>> right answer DEPENDS on the situation.
>>>>
>>>> Wide characters on some platforms are 16 bit which means that when
>>>> you do Unicode you'll still have problems with surrogate pairs
>>>> (meaning that it's still multi (wide) char) so you still have all
>>>> the problems of multi-byte encodings.
>>>>
>>>> You could decide to process everything in a PG specific 4 byte wide
>>>> char and do all text in Unicode but the overhead in processing 4
>>>> times the data is quite significant.  The other option is to store
>>>> all data in utf-8 and have all text code become utf-8 aware.
>>>>
>>>> I have found in practice that the utf-8 option is significantly
>>>> easier to implement, 100% Unicode compliant and the best performer
>>>> (because of reduced memory requirements).
>>>> The Posix API's for locales are not very good for modern day
>>>> programs, I'm not sure where the "mbr*" and the "wcr*" apis are in
>>>> the standardization process but if these are not well supported,
>>>> you're on your own and will need to implement similar functionality
>>>> from scratch and for that matter, the collation functions all
>>>> operate on a "current" locate which is really difficult to work with
>>>> on multi-locale applications.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> ---------------------------(end of
>>>> broadcast)---------------------------
>>>> TIP 8: explain analyze is your friend
>>>>
>>>
>>>
>>> ---------------------------(end of broadcast)---------------------------
>>> TIP 7: don't forget to increase your free space map settings
>>>
>>
>>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if your
>      joining column's datatypes do not match


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